The present invention relates to a tire pressure alarm system, and more specifically to an improved structure for a power switch in a power supply circuit for use in a tire pressure alarm system.
Tires are the "legs" of a vehicle. The tire pressure of the tires of a vehicle must be maintained within a certain range. Excessive high or low tire pressure may affect the movement of the vehicle. Various tire pressure alarm devices have been disclosed for use in monitoring the tire pressure of vehicle tires. Some mechanisms of conventional tire pressure alarm devices are complicated and less accurate. Other conventional tire pressure alarm devices disclose an electronic tire pressure alarm systems. However, a typical electronic type tire pressure alarm system consumes too much battery energy because it employs electronic pressure detection techniques and radio signal transmitting techniques to achieve detection of tire pressure and transmission of the detected signal. Because the electronic type tire pressure alarm system keeps consuming battery energy when the vehicle is stopped, the energy in the battery will be used up within a short period of time. When the energy of the battery is used up, it must be properly disposed of so as not to cause an environmental pollution.